Dynamic kinetic resolution involves the conversion of racemic substrate into a single stereoisomer of the product by inter-conversion of the reactant isomers by racemisation, making removal of one of the isomers as the rate determining step. Dynamic kinetic resolution also overcomes the limitation of conventional kinetic resolution where the maximum yield of one stereoisomer of the starting material or product is only 50%. Dynamic kinetic resolution, though of great significance in asymmetric synthesis to get a single enantiomer of the product from racemic substrate, is not a widespread phenomenon. Only a few cases have been reported so far (R. S. Ward, Tetrahedron Asymmetry, 1996, 1475). However, in these cases the substrates involved are made chirally labile either chemically, biochemically or thermally. There is also a stray reference by F. Toda and K. Tanaka in Chem. Lett., 1983, 661, of converting racemic cyanohydrin into a single enantiomer by complexation with brucine. However, there has been no attempt so far to involve chirally stable racemic epoxides by any means in dynamic kinetic resolution by reaction with amines for obtaining enantiopure .beta.-aminoalcohols that have a high potential as intermediates for the synthesis of wide range of biologically active compounds and as precursors in asymmetric transformations. Until now dynamic kinetic resolution has not been carried out by supramolecular catalysis involving cyclodextrins.
Accordingly, studies were undertaken to see the possibility of involving chirally stable, easily accessible and inexpensive racemic epoxides for the synthesis of enantiopure .beta.-aminoalcohols by dynamic kinetic resolution through supramolecular catalysis in cyclodextrins.